Electroplating rack



Dec. 12, 1967 s. ZAVARELLA ELECTROPLATING RACK Filed April 2, 1965 FIG. 2

IN VENTOR.

ZAVARELLA SAVIN ATTORNEYS United States Patent 3,357,913 ELECTROPLATING RACK Savin Zavarella, Manchester, Conn., assignor to Pilot Company, Inn, East Hartford, Conn., a corporation of Connecticut Filed Apr. 2, 1965, Ser. No. 445,058 6 Claims. (Cl. 204-297) The present invention relates to plating racks and more particularly to a new and improved electroplating rack which may be used in association with an electrolytic bath for depositing a surface coating of metal or the like on individual workpieces.

It has long been known that an electroplating rack may be constructed by bolting or welding together the various component parts of the rack to form a rigid scaifoldlike structure. Unfortunately, bolting and riveting of the parts necessitates the drilling of numerous holes through the components of the rack. Such holes appreciably weaken the structure While the bolts, nuts, and rivets extending therethrough present encumbering projections which protrude outwardly from the rack and which thereby have a tendency to scrape or hit the sides of the plating bath vessel during the plating operation. This results in damaging the usual insulating covering on the plating rack and thereby permits contact between the conductive surfaces of the rack and the electrolytic bath. Addition ally, the construction of a rack using rivets and bolts often results not only in poor conductivity between the parts but also in a structure which rapidly loses its rigidity during the normal operation of plating workpieces. Further, the use of a welded connection requires heating the component parts in the welded area to extremely high temperatures which cause differential annealing of the components and weakening of the structural elements at their junctures. The annealing tends to soften the structural components which thereby allows them to bend more easily and as a result adversely affects the required rigidity of the plating rack. Accordingly, it is an object of the present invention to provide an improved plating rack exhibiting smooth unencumbered surfaces free from apertures and devoid of protruding bolts or rivets.

Another. object of the present invention is to provide an electroplating rack whose components are secured in an improved manner resulting in greater strength at the junctures of the parts and which thereby provides a rack of greater rigidity which facilitates insertion of the rack into the plating bath without contacting the Walls of the electrolyte-containing vessel and thereby substantially reduces the possibility of scrapping or otherwise adversely affecting the insulating coating on the rack.

Still another object of the present invention is to provide an improved electroplating rack which can be assembled in a quick and facile manner, and which nevertheless provides a joint of improved strength that reliably secures the parts over a long service free life.

A further object of the present invention is to provide form-fitted plating rack clips of improved configuration which obviate the necessity of providing apertures and encumbering protrusions on the components of the rack while at the same time providing a tight fit with the mating parts, improved strength therebetween and a facile and economical assembly.

Other objects will be in part obvious and in part pointed out more in detail'hereinafter.

The invention accordingly consists in the features of construction, combination of elements and arrangement of parts which will be exemplified in the construction hereafter set forth and the scope of the application which will be indicated in the appended claims.

"ice

In the drawing:

FIG. 1 is a perspective view partially exploded and partially broken away of an electroplating rack embodying the present invention;

FIG. 2 is an enlarged section view partly broken away taken along the line 22 of FIG. 1, showing a plating rack clip of the present invention; and

FIG. 3 is a perspective view of the clip of FIG. 2 additionally showing a support member, in phantom, in association therewith.

Referring now to the drawing in greater detail wherein like referenced characters indicate like parts throughout the several figures, there is illustrated in FIG. 1 an electroplating rack, generally designated 10, adapted for repeated insertion into an electrolytic plating bath. The rack 10 comprises a plurality of spaced, vertically disposed bus bars 12 which are interconnected by a work-holding assembly that is secured thereto. As shown, the vertical bars 12 are elongated members of generally rectangular cross section throughout their entire length having a pair of opposed longitudinally extending, generally parallel, flat face surfaces 14 and a pair of generally parallel, flat side surfaces 16. The upper end of the bars 12 are shaped to provide books 18 which are adapted to support the plating rack and to suitably engage an electrical conductor for connecting the rack to the electrical circuitry of the plating bath. In this way the bus bars 12 function as supports for suspending the rack 10 within the electrolytic bath and at the same time act as part of the electroplating circuitry.

The work-holding portion of the assembly is securely connected to the bars 12 by means of bar lock clips 20 and comprises a generally horizontal bus bar 22 and a plurality of supported hanger rods 24. The horizontal bar 22 is substantially identical in cross sectional configuration to the main bars 12, but, as illustrated, is substantially straight throughout its entire length, the bars 12 being secured thereto at substantially right angles to the horizontal bar 22. The rods 24 in turn are held against the horizontal bar 22 by means of rod clips 26 and are adapted to support the workpieces being plated.

According to the present invention the bar lock clips 20 provide a form-fitted and secure electrical connection rigidly securing the work-holding portion, and particularly bar 22, to the supporting bars 12. The bar lock clip 20, as best shown in FIG. 3, is a relatively thin sheet metal member of good electrical conductivity having a main body portion 28 which, in the embodiment chosen for illustrative purposes, is generally of square configuration and is provided with a pair of parallel flat surfaces 30, 32. In assembled relationship on the bars 12, 22 the body portion 28 of the clip is sandwiched between the closely spaced face surfaces 14, 34 of the respective bars 12, 22. Thus, the fiat surface 30 is in juxtaposition with the face 14 of the bar 12 while the surface 32 is in juxtaposed relationship with the flat face 34 of the horizontal bar 22.

' Integrally formed with the square body portion 28 of the clip and extending outwardly from the four edges thereof at substantially right angles thereto are two sets of parallel flat flanges 36, 38. The flanges are substantially identical in size, being equal in length to the sides of the square body portion28 and of sufficient width to extend outwardly from the respective flat body surfaces 30, 32 a distance equal to approximately the width of the bus bars 12 and 22. As shown, each of the flanges extends outwardly in a direction opposite to its two adjacent flanges so that one set of parallel flanges 36 will extend at right angles in a first direction from the body 28 while the other set of flanges 38 extends at right angles in the opposite direction. Thus, when assembled on the bars 12 and 22, the clip 20 snugly circumscribes one face surface and two adjacent side surfaces of each bar yet does not protrude outwardly beyond the second face surface or provide other encumbering projections on the rack. As will be appreciated, the flanges 36 and 33, while freely slipping onto the bars into .a position substantially parallel to and in abutment with the sides 16, 49 respectively of the bars 12, 22, nevertheless provide a tight lock fit with the mating parts when a bonding material 42, best shown in FIG. 2, is applied therebetween.

As mentioned hereinbefore, the work supporting portion of the rack 19 is provided with a plurality of hanger rods 24. These rods are rigidly secured to the horizontal bar 22 by means of the form-fitted rod retaining clips 26 which hold them in intimate contact with face 34 of the bar. Each rod 24 has a generally U-shaped portion, generally designated 44, which lies entirely within a single plane parallel to the flat face 34 of the bar 22 and which includes a pair of legs 46 traversing the entire width of j the bar 22 and a curvilinear section 48 which integrally joins the legs and extends slightly above the bar. Each rod 24 additionally comprises a pair of straight free end portions 50 integral with and extending outwardly in a diverging manner from the U-shaped portion 44 at substantially a right angle thereto. In accordance with the present invention, the U-shaped portion 44 is positioned in parallel abutting relationship with the face surface 34 and is fixedly and rigidly secured to the auxiliary bar 22 in such a manner as to prevent encumbering or unnecessary projections on the rack at the area of junction. Additionally, the assembly is of sufiicient strength to prevent loosening of the rod while at the same time assuring good electrical contact between the bar 22 and the rod 24.

The rod retaining clip 26 holding the bar and rod in juxtaposed relationship is preferably an electrically conductive sheet metal member having a central body portion 52 of generally rectangular configuration disposed parallel to and in juxtaposition with the flat face 34 of the bar 22. Upon assembly of the body portion 52 is positioned intermediate the legs of the U-shaped rod portion 44 and covers the full width of the surface 34 in that area. Extending in opposite directions from the body 52 along the longitudinal extent of face 34 are a pair of integral flanges generally designated 54. Each of the flanges 54 are provided with a flat terminal tab portion in substantially aligned coplanar relationship with the body 52 and in juxtaposition with the face 34 of the bar 22. Integrally joining the tab and body portions is an intermediate arcuate portion 58 which extends outwardly from the body and tab portions in a smooth, generally curvilinear manner and defines a semicircular channel 60 adapted to receive and retain the legs 46 of the U-shaped' rod portion 44. The form-fitted clips thus firmly hold the U-shaped rod portion 44 against the face surface 34 of the bar 22 in a rigid and stable manner which ensures good electrical contact there-between.

The component parts of the rack are each firmly adhered by means of a flowable yet hardenable bonding material 42, best illustrated in FIG. 2, which possesses certain important physical characteristics. More specifically, in order to provide maximum rigidity and strength in the structure while. at the same time obviating the adverse effects associated with previously employed connecting means, it is important that the bonding material be applied in a liquid form below a certain maximum temperature limit and yet after application provide a rigid connection through an operating temperature range to maintain the structural integrity of the rack. The bonding material must exhibit a flowable condition suitable for application to the structure at a temperature substantially below about 850 F. and when once applied, solidify and remain firm and stable through an operating temperature range above 375 F., a general working range of 400 F. to 800 F. having been found satisfactory. The bonding material employed should preferably enhance the electrical conductivity of the connection. Accordingly, a

high melting soft solder, such as the tin and antimony containing lead solders exhibiting a melting point of about 500 F. or a lead-silver solder containing from 3 to 4 percent silver and having a melting point of about 430 F., is preferably utilized.

As illustrated in FIG. 2, the bonding material or solder 42 is disposed over substantially the entire opposed surface areas of the clips and the bars, i.e., the entire surface on both sides of the flat bod portion 28 as well as on the inner surfaces of the flanges 36 and 38. Thus, full intimate electrical contact and firm secure bonding is eiiectuated between the bars 12, 22 and the bar clip 20. It will of course be appreciated that the rod retaining clip 26 is likewise fixedly secured to the face 34 of the bar 22 in a manner which is substantially the same as that used for the bar clip 29.

After assembly of the rack but prior to use, it is usually desirable to cover the rack with an insulating coating 62 of plastic or the like. This may be accomplished by first preheating the rack 10 to a uniform temperature prior to application of the insulating coating. The preheating operation may vary depending on the particular insulating material employed; however, when utilizing a plastisol such as a polyvinyl chloride resin dispersed in a plasticizer, a preheating temperature of approximately 350 F. is preferred. With the exception of the end portions of the hanger rods 24 and a substantial portion of the hook 18, as shown in FIG. 1, the entire rack is dip-coated with the polyvinyl chloride plastisol for a sufiicient period of time to produce an insulating coating of the desired thickness. Generally, a coating of less than 30 mils is insufficient since scufiing may readily expose the metal surfaces to the electrolytic bath. Accordingly, it is preferred that the plastisol coating have a thickness of approximately 60 mils or greater in order to provide the desired protection. Upon removal of the rack from the viscous coating fluid, the entire assembly is reheated to a temperature of approximately 350 F. to firmly bake or cure the plastisol and form the firm solid insulating coating 62.

The bars, rods, and clips utilized in accordance with the present invention are highly conductive metallic materials capable of being readily joined by the hardenable bonding material 42. It is generally preferred that these components be cold worked temper materials. For ex ample, half-hard drawn copper bars which permit form ing of the hook portions 18 without substantial cracking have been used with good results for the bus bars 12,22 while the clips and rods, may be constructed of spring temper stainless steel of standard sheet metal thickness.

As will be appreciated from the foregoing detailed description, the present invention provides an improved elec troplating rack exhibiting greater strength at the junctures of the component parts. The rack obviates the necessity for drilling holes which tend to weaken the structure or for employing bolts or rivets which protrude outwardly from the rack in an undesirable manner and which have a tendency to loosen during the normal operation due to the extreme operating conditions to which the" rack is subjected. The rack further employs tight preformedclips which contribute to excellent electrical conductivity be tween the joined components and aid inprovidinga' structure which remains sturdy and rigid' during a long useful life.

As will be apparent to persons skilled in the art, various modifications and adaptations of the structure abovedescribed will become readily apparentwithout departure from the spirit and scopeof the invention, the scope of which is defined in the appended claims.

I claim: 7

1. An electroplating rack devoid of apertures and unencumbered by protrusions comprising an elongated bus bar of rectangular cross section having a longitudinally extending fiat face; a holder for a workpiece electroconductively joined to the bar; and an unperforated sheet metal clip securely joining said bar and said holder in a fixed relative position, said clip being provided with a flat generally rectangular body portion parallel to and in juxtaposition with the flat face of said bar and an integral flange portion form-fitted against and tightly engaging said holder, said clip being fixedly secured to said bar and said assembly solely by a flowable bonding material having a melting point above 375 F. and below 850 F.

2. An electroplating rack free from apertures and unencumbered by protrusions comprising a first elongated bus bar; a second bus bar angularly positioned with respect to said first bar, each of said bars being of generally rectangular cross section and provided with a longitudinally extending flat face portion and adjacent side portions, said first bar having on One end thereof a hook adapted to position said rack for electroplating while making contact with an electric circuit; and an unperforated sheet metal clip electroconductively joining said first bar and said second bar in a fixed relative position, said clip being provided With a flat generally rectangular body portion having opposite faces in juxtaposition with one flat face of each bar and flat integral flanges extending outwardly at right angles from the edges of said body, said flanges juxtaposed to the sides of said bars and tightly locking said clip onto said bars, said clip being fixedly secured to said bars solely by soft solder having a melting point greater than 400 F. and less than 800 F.

3. An electroplating rack free from apertures and devoid of encumbering protrusions comprising a first elongated bus bar; a second bus bar disposed at a right angle to said first bar, each of said bars being of generally rectangular cross section and provided with a longitudinally extending flat face portion bounded by a pair of side portions, said first bar having on one end thereof a hook adapted to vertically position said first bar Within an electroplating bath while making contact with an electric circuit for said bath; and an unperforated form-fitted sheet metal clip electroconductively joining said bars in a fixed relative position, said clip being provided with a flat generally square body portion having opposite faces in juxtaposition with one flat face of each bus bar and a flat integral flange extending outwardly from each of the four edges of said body at right angles to said body, each of said flanges extending in a direction opposite to its next adjacent flange whereby pairs of opposite flanges are juxtaposed to the sides of the bar disposed therebetween to tightly lock said clip onto said bar, said bars and clip being of cold-worked temper material annealable at about 850 F. and above, said clip being fixedly secured to said bars solely by soft lead solder having a melting point greater than 400 F. and less than 800 F.

4. An imperforate electroplating rack free from encumbering protrusions comprising an elongated bus bar of rectangular cross section having a flat longitudinally extending face portion; an electrically conductive hanger rod fixedly secured to said face portion and adapted for supporting a workpiece, said rod having a first portion thereof abutting the fiat face of said bar and maintaining electroconductive contact therewith and a second portion extending outwardly from said face at a right angle to said first portion; and a rod retaining clip comprising a flat generally rectangular body portion parallel to and in juxtaposition with the face of said bus bar and an integral flange engaging said first rod portion, said flange having a flat tab portion coplanar with the body portion and an intermediate arcuate portion joining said body and tab portions and extending outwardly from the bar face to form a tight fitting channel adapted for receiving and retaining therein said first rod portion, said clip being secured to said bar and said rod solely by flowable bonding material having a melting point greater than 400 F. and less than 800 F.

5. An imperforate electroplating rack free from encumbering protuberances comprising an elongated bus bar of rectangular cross section having a flat longitudinally extending face portion; an electrically conductive hanger rod fixedly secured to said face portion and adapted for supporting a workpiece, said rod having a first U-shaped portion abutting said flat face across its entire width and maintaining electroconductive contact therewith and a pair of free end second portions integral with said first portion and extending outwardly from said face at a right angle to said first portion; and a rod retaining clip comprising a flat generally rectangular body portion parallel to and in juxtaposition with the face of said bus bar and a pair of integral flanges oppositely extending from said body portion longitudinally along said bar face, each of said flanges including a flat tab portion coplanar with the body portion and an intermediate arcuate portion joining said body and tab portions, said arcuate flange portions forming a pair of tight fitting channels adapted for receiving and retaining therein the legs of said U-shaped rod portion, said clip being secured to said bar solely by soft solder having a melting point greater than 400 F. and less than 800 F.

6. An electroplating rack free from apertures and unencumbered by protrusions comprising a first elongated bus bar; a second elongated bus bar angularly disposed with respect to said first bar, each of said bars being of generally rectangular cross section and provided with a longitudinally extending flat face portion and adjacent side portions, said first bar having on one end thereof a hook adapted to position said rack for electroplating While making contact with an electric circuit; an unperforated bar clip of sheet metal electroconductively joining said first bar and said second bar in a fixed relative position, said bar clip being provided with a flat body portion having opposite faces in juxtaposition with the flat face of each bar and two pairs of flat integral parallel flanges extending outwardly at right angles from the edges of said body, said pair of parallel flanges being in juxtaposition with the sides of said bars respectively for locking said clip onto said bars; an electrically conductive hanger rod fixedly secured to the face portion of the second bar and adapted for supporting a workpiece, said rod having a first portion thereof in juxtaposition with the face portion of said second bar and maintaining electroconductive contact therewith and a second portion extending outwardly from the bar face of the second bar at a right angle to said first portion; and a rod retaining clip comprising a flat generally rectangular body portion parallel to and in juxtaposition with the bar face of the second bar and an integral flange having an arcuate portion extending outwardly from said body portion to form a tight fitting channel adapted for receiving and retaining therein said first rod portion, the bar lock clip and the rod retaining clip being secured to the bars solely by a flowable bonding material having a melting point greater than 400 F. and less than 800 F.

References Cited UNITED STATES PATENTS 2,858,265 10/1958 Schneider 204297 3,032,494 5/1962 Belke 204297 OTHER REFERENCES Belke Plating Rack Manual, pp. 22 and 23, 1947. Copy in Group 114.

HOWARD S. WILLIAMS, Primary Examiner.

D. R. JORDAN, Assistant Examiner. 

1. AN ELECTROPLATING RACK DEVOID OF APERTURES AND UNENCUMBERED BY PROTRUSIONS COMPRISING AN ELONGATED BUS BAR OF RECTANGULAR CROSS SECTION HAVING A LONGITUDINALLY EXTENDING FLAT FACE; A HOLDER FOR A WORKPIECE ELECTROCONDUCTIVELY JOINED TO THE BAR; AND AN UNPERFORATED SHEET METAL CLIP SECURELY JOINING SAID BAR AND SAID HOLDER IN A FIXED RELATIVE POSITION, SAID CLIP BEING PROVIDED WITH A FLAT GENERALLY RECTANGULAR BODY PORTION PARALLEL TO AND IN JUXTAPOSITION WITH THE FLAT FACE OF SAID BAR AND AN INTEGRAL FLANGE PORTION FORM-FITTED AGAINST AND TIGHTLY ENGAGING SAID HOLDER, SAID CLIP BEING FIXEDLY SECURED TO SAID BAR AND SAID ASSEMBLY SOLELY BY A FLOWBLE BONDING MATERIAL HAVING A MELTING POINT ABOVE 375*F. AND BELOW 850*F. 